Weil-McLain Ultra Commercial Installation And Start-Up Manual page 17

COMMERCIAL GAS
Install water piping
Zoning with zone valves — alternate
High-flow-rate/high-head-loss DHW circuits
1. For applications requiring DHW circuit flow rates higher than al-
lowable for the boiler, or for high pressure-drop coil-type DHW
tanks, connect the piping as in Figure 9. The DHW water only flows
through the secondary circuit connection piping. NOTE: Make
sure to size the connection piping (Figure 9, item 23) to handle
the total flow it must handle.
2. Connect boiler to system as shown in
zoning. The primary/secondary piping shown ensures the boiler
loop will have sufficient flow. It also avoids applying the high head
of the boiler circulator to the zone valves.
3. When using a closed-type expansion tank, connect the expansion
tank and make-up water piping as shown in Figure 7, page 15.
4. Connect DHW (domestic hot water) piping to indirect storage
water heater as shown.
5. Controlling the system circulator and boiler circulator
a. If DHW input is priority 1: With factory default, on a call for
DHW heating, the U-Control turns circulator 1 (DHW) and
circulator 4 (boiler) ON and turns circulators 2 and 3 OFF (so
there is no space heating during DHW operation). Read the
instructions on U-Control operation and setup, beginning on
page 58 for further information.
For systems with low-temperature radiant heating, the
system circulator (item 7) MUST be OFF during DHW
heating to prevent possible overheating in the radiant
system.
1 Ultra boiler
2 Indirect water heater (DHW), if used
3 Boiler relief valve (see page 13 for piping details)
4 Relief valve discharge piping (see page 13 for details)
5 DHW circulator
6 Isolation valves
7 System circulator (see information above for wiring)
8 Diaphragm (or bladder) type expansion tank (see page 15 for piping of
closed-type expansion tank, if used)
9 Air separator [with automatic air vent only on systems using diaphragm
(or bladder) type expansion tank]
10 Flow/check valves
11 Purge/drain valves
12 Boiler circulator
13 Zone valves, typical
20 Make-up water supply
21 Primary/secondary connection (tees no more than 8 pipe diameters
apart)
Part number 550-100-086/0809
-
FIRED WATER BOILER
(continued)
Figure 9 when zone valve
Legend — Figure 9
— Boiler Manual
Zone valve zoning plus optional DHW
piping
23 DHW secondary connector piping — no more than 8 pipe diameters
apart
24 Strap system supply and return sensors to lines as shown, at least 6 pipe
diameters (but no more than 3 feet) from boiler connection tees.
25 Systems using high-head pumps may require a bypass pressure regulator
to prevent damage to control valves.
26 Boiler drain valve, ¾" or larger
31 Install a union on the boiler supply and return connections as close as
possible to the boiler to allow disconnection for service when required.
Items supplied with boiler
Items supplied by others
Use at least the following pipe sizes on all boiler
NOTE 1:
loop piping (connecting boiler to and from the
primary/secondary connection, item 21). Pipe sizing is based on a temperature
rise of 30°F, corresponding to the recommended maximum flow rate. Use only
primary/secondary piping as shown. Failure to follow these guidelines could
result in system problems.
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